RF antennas such as an antenna for telephone communication, an antenna for GPS, an antenna for wireless LAN/BLUETOOTH (registered trademark), and RFID (Radio Frequency Identification) are mounted in a wireless communication device in recent years. In addition to the above antennas, a loop coil for transmitting power has also been mounted with introduction of non-contact charging. As power transmission methods used for the non-contact charging, there are an electromagnetic induction method, a radio wave reception method, a magnetic resonance method, and the like. All of these methods use electromagnetic induction and/or magnetic resonance between a primary coil and a secondary coil. For example, electromagnetic induction is used in Qi standard for non-contact charging and NFC (Near Field Communication) standard of RFID.
In an antenna module, it is required for an antenna coil to receive magnetic flux equal to or greater than a certain value from a transmitter of a reader/writer or the like in order to reliably perform communication. Therefore, in an antenna module according to a conventional example, a loop coil is provided in a housing of a mobile phone and the coil receives the magnetic flux from the reader/writer.
For example, as a method for improving the characteristics of a loop antenna included in a mobile terminal device, Patent Document 1 proposes a method of arranging a flexible cable and a flat cable around a built-in battery.